Making an AlertDialog in Flutter

This is a repost of an answer I wrote on Stack Overflow.

If you need to display a message to a user and give them time to read it or request a response from them, you can use an AlertDialog. This is the equivalent of an Android AlertDialog or an iOS UIAlertController. The examples below show a basic setup for one, two, and three buttons.

One Button

showAlertDialog(BuildContext context) {
  // set up the button
  Widget okButton = FlatButton(
    child: Text("OK"),
    onPressed: () { },
  );
  // set up the AlertDialog
  AlertDialog alert = AlertDialog(
    title: Text("My title"),
    content: Text("This is my message."),
    actions: [
      okButton,
    ],
  );
  // show the dialog
  showDialog(
    context: context,
    builder: (BuildContext context) {
      return alert;
    },
  );
}

Two Buttons

showAlertDialog(BuildContext context) {
  // set up the buttons
  Widget cancelButton = FlatButton(
    child: Text("Cancel"),
    onPressed:  () {},
  );
  Widget continueButton = FlatButton(
    child…